The anomalous Hall effect due to an intrinsic magnetic ordering combined with topological electronic states is at the forefront of recent study in condensed matter physics. The seminal compound ${\mathrm{MnBi}}_2{\mathrm{Te}}_4$ has fueled an enormous amount of interest in the study of various exotic quantum phenomena such as the axion insulator state, the Chern insulator state, and the quantum anomalous Hall effect on this material as well as its heterostructural cousins (${\mathrm{MnBi}}_2{\mathrm{Te}}_4){\left({\mathrm{Bi}}_2{\mathrm{Te}}_3\right)}_n$. Despite the theoretically expected gapped Dirac surface states in these time-reversal symmetry broken topological materials, the electronic band structures are variously reported with regard to the presence of the band gap in the Dirac cone. Here we report on Sb-doped higher-order Mn-Bi-Te magnetic topological materials in our combined study of magnetotransport and angle-resolved photoemission spectroscopy. We found multiple magnetic ground states in the Sb-doped antiferromagnetic topological insulator ${\mathrm{MnBi}}_4{\mathrm{Te}}_7$, driven by a delicate balance of magnetic interactions along the van der Waals interlayer direction. Additionally, we detected a gradual shift of the Fermi level from the conduction band to the valence band, accompanied by charge compensation at approximately 33% Sb doping. Interestingly, we observed the gapless Dirac states in pristine ${\mathrm{MnBi}}_4{\mathrm{Te}}_7$ and the gapped states in Sb-doped ${\mathrm{MnBi}}_4{\mathrm{Te}}_7$. We explored this unconventional scenario in the light of recent studies from various research groups.

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• Electronic structure
• Hall effect
• Magnetism
• Magnetotransport
• Topological materials
• Angle-resolved photoemission spectroscopy